The current code does schedule_timeout(HZ) when waiting for a cpu to die,
which is a bit coarse and tends to limit the "throughput" of my stress
tests :)

Change the HZ timeout to HZ/5, increase the number of tries to 25 so the
overall wait time is similar.  In practice, I've never seen the loop need
more than two iterations.
Signed-off-by: Nathan Lynch <nathanl@austin.ibm.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>